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You need to add as many 'stimulusonset' columns as your <trial>s present stimuli. I.e. with
<trial mytrial> / stimulustimes = [0=a; 500=b; 1000=c] ... </trial>
<data> / columns = [..., stimulusonset, ...] ... </data>
will only capture the onset for 'a', while
/ columns = [..., stimulusonset, stimulusonset, ...]
will capture onsets for 'a' and 'b', and
/ columns = [..., stimulusonset, stimulusonset, stimulusonset, ...]
will capture onsets for 'a', 'b' and 'c'.
You will find this covered in the documentation topics mentioned previously. See the 'Remarks' section for the /columns attribute:
"Stimulusnumber, stimulusitem, stimulusonset, and "string" receive special treatment. The first stimulusnumber specified in the columns attribute indicates that the item number of the first stimulus appearing on the current trial should be recorded. The second stimulusnumber indicates that the item number of the second stimulus presented on the trial should be recorded, and so on. If no 1st, 2nd, 3rd, etc. stimulus is presented on a given trial, a '0' is recorded. Similarly, the first stimulusitem specified in the columns attribute indicates that the actual item presented by the first stimulus appearing on the current trial should be recorded. If the stimulus is <text> or <port>, the actual item is recorded. If the stimulus is a <sound>, <picture>, or <video>, the item's filename is recorded. If the stimulus is a <shape>, the name of the shape is recorded. Like stimulusnumber, each successive stimulusitem records the item from each successive stimulus presented on the trial. If no 1st, 2nd, 3rd, etc. stimulus is presented on a given trial, a '0' is recorded. Similarly, the first stimulusonset specified in the columns attribute indicates that the onset time of the first stimulus appearing on the current trial should be recorded."
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Thanks. Our format looks unfortunately a bit different from the one you described. I sent it to you in a pm. We would be very grateful if you can show us how it is done in our case. Since it is not our own task, could you please not put our syntax public? Many thanks!
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Group: Administrators
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FYI: I have received & responded to your PM.
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Group: Forum Members
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Dave, thanks for your quick response! Now we tried one of your earlier suggestions. The results of the laptop which showed the pictures much longer than the intended 67 ms (laptop 1) are: display.refreshrate: 60 computer.cpuspeed: 1995 computer.timerresolution: 0,0000698412787100036
The results of a laptop that shows the intended 'flash' (laptop 2):display.refreshrate: 60 computer.cpuspeed: 1896 computer.timerresolution: 0.0005401708884622739
A third computer (not a laptop) which also shows the intended flash has results: display.refreshrate: 60 computer.cpuspeed: 3193computer.timerresolution: 0,0002793651148400146
So how to interpret these results? Do you (or anyone else) know whether these results are related to our problem that on laptop 1 our emotionrecognitiontask does not function properly and the facial emotion pictures are shown for much longer than the intended 67 milliseconds? I do notice that the timerresolution of computer 1 seems low compared to the others but don't know whether this is a meaningful difference.
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Group: Administrators
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Those results do not indicate any problem with the affected machine and as such do not offer any indication with respect to the underlying issue. I would (still) consider a problem with the machine's display system (graphics card hardware, its driver, interaction with the OS) the most likely culprit. Has the system's display driver been updated to the latest release version available from the vendor?
Also, what happens when you examine the results of a *different* script on the affected machine? You could code up a quick, simple script that displays the same image stimuli used in your existing script in a simple <trial>
<trial sometrial> / stimulustimes = [0=image; 67=blank] ... </trial>
and examine the reported onsets.
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